Bearing for disk grinders.



J. MILLER, JR.

BEARiNG FOR DISK GRINDERS.

APPLICATION FILED APR. 30. 1917.

1 72,493, Patented July 16, 1918.

2 SHEETS-SHEET l.

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I. MILLER, IR.

BEARlNG FOR DISK GRINDERS.

APPLICATION HLED APR. 30. 1917.

1 72,493 Patented July 16, 1918 2 SHEETS-SHEET 2.

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'1 I t l 1" 39 1 I U U 7 n U 0 F i y' I 6 i I is -L----'- i V 3 Y. A

JOHN MILLER, 33., OF BELOIT, WISCONSIN, ASSIGNOR T0 CHARLES H. BESLY & COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

BEARING FOR DISK GBJNDERS.

Specification oi Letters Eatent.

Patented July id, 1918.

Application filed April 30, 1917. Serial No. 135,331.

for supporting the disk spindles of grinding machines and the method of lubricating the same, these features bein of considerable importance in machines 0 this type, as will be understood from the general discussion which follows.

The so-called disk grinder differs from the ordinary grinding machine in that the work is brought against the side or flat face of the grinding disk, rather than against the circumferential face or rim of the wheel, the grinder being mounted upon a rotative spindle and the work moved toward and against the disk upon a sliding carriage or work table. The pressure thus exerted upon 7 the disk is manifestly transmitted longitudinally of the spindle, creating what is ordinarily known as end thrust. By the very ,mode of operation, therefore, the end thrust in machines of this character is considerably greater than in the ordinary machine tool, and it follows that an adequate arrangement of bearings must be provided,

not only to support the spindle in its rotative motion, but to resist the end thrust of the spindle.

A desirable type of machine of this character is known as a double ended machine, that is, having two grinding disks mounted upon the spindle, which may be used simultaneously, the work being forced against the disks from opposite directions, by means of sliding feed tables arranged in parallel relation to the spindle. For this reason the end thrust is not only excessive, as hereinbefore pointed out, but is equally so in both directions, thus necessitating the use of hearings to take up the end thrust in both directions. A preferable construction for a hearing to meet the conditions existing in a disk grinder, is a bearing bushing having a lain or radial bearing surface and end t rust bearing surfaces, that is, a radial bearing having thrust bearing surfaces at both ends. This arrangement provides a simple, compact, and highly desirable form of bearing, inasmuch as it requires no increased length of spindle to accommodate the parts of the bearing, and greatly simplifies the lubrication thereof, as will hereinafter be pointed out. A bearing of this type would manifestly include complementary bearing surfaces upon the spindle in the form of fixed thrust collars, which embrace the bearing bushing between them. in order to secure a high degree of accuracy in the work produced by these machines, it is important that end play in the shaft be eliminated, so that the plane of rotation of the disks will not be varied. Furthermore, the longitudinal expansion of the bearing bushing must be considered, the expansion or elongation being due to the heating up of the bearing in service. It follows, therefore, that, if the thrust collars are located in close relation to the bearing bushing, thus eliminating the end play, the expansion of the bushing would ordinarily produce a binding between the bearing surfaces, or develop a tendency to shift the spindle endwise in one direction or the other, thereby throwing the disk out of its predetermined plane of rotation. For this reason it is proposed to provide means for taking up the expansion of the bearing bushing at a point intermediate its ends, thus maintaining the same of uniform length between the end bearing surface and avoiding the results hereinbefore pointed out.

Of equal importance. is the manner of lubricating the bearings, it being desirable, first, to employ an automatic system. of lubrication, that is to say, a system which requires but little manual attention; and, secondly, a system wherein all lubricated surfaces are inclosed in dust-proof casings, so that dust and dirt which is prevalent around grinding machines cannot enter the bearings. The more common method of lubricating bearings of machine tools is by means of grease cups mounted exterior of the bearings, which require frequent refilling by the operator or attendant, and, furthermore, are exposed to an atmosphere laden with dust and grit, and, as a result, the foreign matter becomes mixed with the grease in the filling of the cups and ulti- 11o matel works into the bearings with harmful, if not damaging results. This mode is further open to the objection that attendants often neglect to fill the-cups with grease, and the injuries to the bearings due to insuflicient lubrication are the results.

It is the purpose of this invention to provide a bearing particularly suited for disk grinders and embodying novel features of construction calculated to improve the operation and maintenance of such machines, and more especially with respect to the matters hereinbefore discussed.

The features of construction embodying the invention are more fully described in the description which follows, and illustrated in the accompanying drawings, wherein- Figure l is a view in elevation of a disk grinding machine of the type embodying the features of the invention;

Fig. 2 is an enlarged view in vertical section taken through the head stock and bearings of the machine;

Fig. 3 is a plan view of the head stock and bearings with bearing caps removed;

Fig. 4 is a plan view of the bearing cap removed, the same being a part of the lefthand bearing shown in Fig. 2;

Fig. 5 is a plan view of the other bearing cap removed, the same being a part of the right-hand bearing shown in Fig. 2; and

Fig. 6 is a cross-sectional view taken on line 66 of Fig. 2.

A grinding machine embodying the features of the invention comprises an upright pedestal or base 10, provided at its upper end with two head stocks 11 spaced apart to provide a centrally disposed space there between. A horizontally arranged spindle 12 is rotatably mounted in bearings within said head stocks 11, and has, at its central portion and intermediate the head stocks 11, 1-1, a fixed driving pulley 13, and at its outer ends, which project beyond the ends of the head stocks 11, 11, two grinding disks 14, 14. Below the grinding disks 14, 14 and rigidly mounted on the pedestal 10 are shafts 15, 15 projectin outwardly from opposite sides of the pe estal and in parallel relation to the spindle 12. Mounted upon each of said shafts 15 is a hub 16, said hub having the form of a split bearing, adapted to be rigidly fixed to the shaft by means of suitable clamping screws, and likewise to be adjusted lengthwise of the shaft or to be oscillated about said shaft in a plane parallel to the face of the grinding disk. The hub 16 carries an upright arm 17, which is provided with a vertical slot 18, which embraces two adjusting screws 19, adapted to permit the vertical adjustment of the arm. At the upper end of each arm 17 is mount ed a horizontally disposed base plate 20, extending at right angles to the face of the adjacent grinding disk 14. Slidably mounted upon each base member 20 is a work or feed table 21, to the upper surface of which the article or work to be ground is secured. The work tables 21, 21 are movable endwise toward and. from the outer faces of the grinding disk by means of a rack and pin- 10H connection, which is not shown in detail in the drawings but which will be clearly understood from the following. Each work table 21 is provided with rack teeth adjacent the outer end thereof, said rack teethmeshing with a pinion mounted upon a vertical shaft having bearing in a base plate 20 and extending below'the same,- said shaft carrying a lever arm 22 adapted to be swung or oscillated in a horizontal plane b the hand of the operator, thereby transmltting through the rack and pinion an endwise movement to the feed table, to advance and withdraw the work from the surface of the grinding disks. In order to accurately gage the grinding operation, the feed table 1s provided with a micrometer adjustment, comprising a micrometer screw 23 supported in an arm 2'4 extending beyond the outer end of the base plate 20, said micrometer screw being adjustable endwise by a suitable micrometer head 25, to engage the end surface of the base plate 20, thus limiting the distance to which the feed table 21 may approach the surface of the grinding disks. /In addition to the parts already described,

'the work feeding-mechanism comprises also a counter-weight 26, which is mounted upon a shaft 27 fixed to and depending from the hub 16. The purpose of the counterweight is to effect the return of the feed table to a vertical position when the hub is loosened and thus permitted to oscillate about the shaft 15.

Referring now in detail to the bearings which support the spindle and which are designed especially to fulfil the requirements of a machine functioning as hereinbefore set forth, the said bearings are two in number, each being located in the head stocks 11, 11. As shown in Fig. 2, the head stocks are constructed in a manner not unlike the practice followed in the manufacture of machine tools, namely, comprising a cylindric casing formed integral with the pedestal 10, this casing being divided or split along a horizontal plane coinciding with the axis of the spindle, the upper portion forming a cap 28, which is secured to the lower portion or half by the usual arrangement of studs or cap screws 29. In the general features of construction, the head stocks 11, 11 are similar, as will appear from the following. The space inclosed by the head stocks is divided into a series of vertical and parallel spaces or. recesses 30 by means of a series of vertically arranged walls 31, said walls being provided with annular openings forming the seat for the bearing bushing,

the oil chamber.

hereinafter to be described. The recesses 30 extend below the central axis of the head stock, and form with the bottom walls of the head stock a chamber or oil reservoir of considerable depth and capacity, the several recesses communicating with each other at their lower ends by the provision of transverse passages 32.

Within the head stocks, on the right and left-hand sides of the driving pulley 13-, respectively, are mounted bearing bushings 33 and 34, composed of Babbitt metal, phosphor bronze, or like anti-friction metal, said bearing bushings being of the usual split form, consisting of two halves, which are parted along a horizontal plane, the lower half resting in seats formed by the partition walls 31 and fixed in place by means of anchor pins 35, 35 extending vertically upward through one of the partition walls 31 and engaging holes 35 formed in the bottom surface of the bushing, these holes being slightly elongated longitudinally to allow for the expansion or elongation of the bushing. The upper half of the bearing bushing is provided intermediate its ends with two radially disposed grooves 36 formed in the bearing surface thereof and surrounding the spindle 12, the bushing being provided with increased thickness of metal adjacent said grooves and having the form of semicircular flanges 37. These channels 36 are spaced inwardly from the ends of the bushing and preferably in registering relation with the central or innermost recesses 30, 30 of the head stock. Within these channels 36 and surrounding the spindle 12 are oil rings 38, 38, having a diameter considerably greater than that of the spindle, said rings depending downwardly from the spindle, with their lower portions terminating adjacent to the bottom of the oil chamber or reservoir. The oil rings are rotated by contact with the rotative spindle, thus supplying oil to the surface of the spindle from The oil thus supplied to the bearings and spindle, at the oil rings, is distributed len hwise throughout the entire bearing sur ace, by the provision of suitably arranged oil grooves 39.

Referring now to the right-hand bearing, as illustrated in Fig. 2, the bearing bushing 33 thereof differs from the left-hand bushing 34 in respect to the following features. At the ends of said bushing 33 are provided flanges 40, 40, the outer faces thereof forming bearing surfaces of an area considerably greater than the uniform cross-sectional area of the bushing and constituting the end thrust bearing surfaces. Embracing the bearing bushing 33, and having bearing contact with the end surfaces thereof, are thrust collars 41, 41, the same being mounted upon the spindle 12 and fixed thereto in the following manner, The thrust collar 41 at the outer end of the bearing is connected to an oil ring 42 by means of a transverse pin 43, said oil ring 42 being in turn connected to .a collar 44, which is rigidly fixed to the end of the spindle and supports one of the grinding disks, as-shown in Fig. 1, said oil ring 42 and disk collar 44 being connected together by a pin 45. The inner thrust collar 41 is directly connected to the spindle 12 by means of a pin 46, there being provided beyond said thrust collar an adjusting collar 47 having screw-threaded engagement with the spindle and adapted to be moved endwise to take up the end play in the spindle.

The function of the oil rings in this bearing is the lubrication of the radial bearing surface and, in addition, the lubrication of the end thrust bearing surfaces, the oil being carried upwardly from the oil chamber, by means of the rings 38, as before described, to the bearing surface of the bushing, and from there conducted longitudinally of the radial bearing surface to the end thrust bearing surfaces by means of the oil grooves 39, which extend to the inner edges of said end bearing surfaces. The distribution of the oil throughout the thrust bear ing surfaces may be further facilitated by the provision of oil grooves formed in the end surfaces, arranged in any suitable manner to effect a uniform and adequate supply of oil to the bearing surfaces, as for instance an arrangement of circular grooves arranged eccentrically to the central axis of the bushing, and radial connecting grooves extending from the ends of the longitudinal grooves 39 to said eccentric grooves. It is clear that the oil rings 38, 38 of the combined radial and end thrust bearing bushing 33, serve to lubricate both surfaces, with the aid of the oil grooves for conducting the oil not only throughout the length of the radial bearing surface, but also to the end thrust bearing surfaces.

As a means for taking up the longitudinal expansion of the bushing, the following construction is employed. At the central portion of the bushing, there is provided a' clearance space as at 48, this space being formed by dividing the bushing transversely midway between its ends, thus dividing it into two sections placed end to end and spaced apart a predetermined distance, calculated to permit the free expansion of the twosections toward their adjacent ends. By the provision of the central clearance space, it is manifest that, if the bushing undergoes expansion or elongation, such expansion will be in the direction of the central portion of the bearing, that is, from each end of the two sections thereof toward the clearance space, the latter permitting such expansion to take place freely. In this manner the length of the bearing bushing between the thrust bearings remains constant, in spite .face, adapted to contact of the Varying degrees of expansion, thus all tendency of binding or displacing of the spindle is eliminated. Inasmuch as the bushing 33 consists of two separate sections, there is provided an anchor pin 35 for each section and an' elongated hole adapted to receive each pin, in the same manner and for the purpose hereinbefore described.

Among the advantages resulting from the structure herein described may be mentioned the following: First, the bearings of the spindle are lubricated in a manner practically automatic, requiring no attention with the exception of replenishing the oil chamber. Secondly, all parts of the bearing are inclosed in a dust-proof casing, hence no danger'of foreign matter working into the bearing, with damaging results. Thirdly, the type of bearing embracing in a single member both a radial and thrust bearing, provides a simple and economical arrangement, both as to space required and to lubrication, inasmuch as both are lubricated by the same member; and, lastly, the provision of a clearance space between the ends of a bearing having thrust bearing surfaces at each end, makes such a construction entirely practical, since it eliminates the effect of expansion, as hereinbefore pointed out. All of these advantages manifestly operate to materially improve the construction and operation of machines of the type hereinbefore described, and more particularly the amount and quality of the work produced thereby.

I claim as my invention:

1. In a grinding machine, the combination of a head stock, a spindle, a bearing bushing for said splndle, mounted in said head stock and provided with a radial bearing surface and at each end with a thrust bearing surwith thrust collars fixed on said spindle, and said bushing being so formed as to permit the same to ex pand longitudinally.

2. In a grinding machine, the combination of a head stock, a spindle, and a bearing bushing mounted in said head stock and provided with a radial bearing surface and at each end with a thrust bearing flange adapted to have contact with thrust collars fixed on said spindle, and said bushing being divided intermediate its ends to form a clearance space.

3. In a grinding machine, the combination of head stocks spaced apart, a spindle mounted in said head stocks, bearing bushings mounted in said head stocks and surrounding said spindle, one of said bearing face and end flanges forming thrust bearing surfaces, adapted to engage thrust collars fixed to said spindle, said bearing bushing being divided transversely intermediate its ends, to form a clearance space, and means for anchoring each section of said bushing in said head stock.

5. In a grinding machine, the combination of a head stock, a spindle mounted in said head stock, a bearing bushing mounted in said head stock and provided at its ends with thrust bearing surfaces, said bushing being divided transversely midway of its ends into sections, to provide a clearance space at the point of division, and means for anchoring each of said sections to said head stock.

6. In a grinding machine, the combination of a head stock, a spindle, a bearing bushing for said spindle, mounted in said head stock and provided with a radial bearing surface and with oppositely facing thrust bearing surfaces, adapted to contact with thrust collars fixed to said spindle, and said bushing being divided transversely into two parts so as to permit each part to expand longitudinally in a direction away from the thrust collar with which it contacts.

7. In a grinding machine, the combination of a head stock, a spindle, a bearing bushing for said spindle mounted in said head stock and provided with a radial bearing surface and with oppositely facing thrust bearing surfaces, adapted to contact with thrust collars carried by said spindle, said its ends to form a clearance space, and means for anchoring each section of said bushing in said head stock, comprising a fixed member on one of such parts extending into an elongated slot in the other of such parts.

In testimony that I claim the foregoing as my invention, I aflix my signature in the presence of two Witnesses, this 27th day of April, A; D. 1917.

JOHN MILLER, JR.

Witnesses: M. C. PIERCE, E. M. VAN LONE.

bushing being divided transversely between 

